1. Field of the Invention
The present invention relates to a condenser for forced air cooling and in particular relates to a forced air-cooling condenser that is used in a refrigerator of a construction wherein a condenser arranged at the bottom of the refrigerator is forcibly cooled by the blowing action of a cooling fan.
2. Description of the Related Art
Conventionally, refrigerators exist in which a freezer compartment and the refrigerator compartment etc are constituted within a thermally insulated box; the interior of the compartments is cooled by arranging an evaporator of a cooling device within the freezer compartment, and arranging the compressor and/or condenser of the cooling device within a machinery compartment constituted at the bottom of the thermally insulated box; these are arranged to be forcibly cooled by blowing external air into this machinery compartment, using a blower.
FIG. 14 shows a cross-sectional view of the portion of a machinery compartment 102 of a refrigerator 101 of this type.
In this Figure, an external air intake port 103 is formed on the right-hand side of the rear face of machinery compartment 102 and an external air exhaust port 104 is formed on the left-hand side of the rear face. Condenser 105 of the cooling device is arranged on the right-hand side within this machinery compartment 102, and compressor 106 of the cooling device is arranged on the left-hand side. Also, a blower (cooling fan) 108 operated by motor 107 is arranged between condenser 105 and compressor 106.
In the construction as described above, when motor 107 of blower 108 is operated, external air is taken in from intake port 103 of machinery compartment 102, and passes through condenser 105 to cool this condenser 105. After this, the external air reaches compressor 106 through blower 108, cooling this compressor 106, after which it is evacuated from exhaust port 104 (the flow of external air (cooling air current) in this process is shown by arrows in FIG. 14). By this means, condenser 105 and compressor 106 are forcibly air-cooled by external air.
Condenser 105 that is forcibly air-cooled as described above may also be a so-called auxiliary condenser arranged so as to supplement the cooling performance of another, main condenser (not shown).
As the forcibly cooled condenser (also including an auxiliary condenser) described above, a condenser 111 of the construction shown in FIG. 15 or a condenser 121 of the construction shown in FIG. 16 were generally used conventionally.
The condenser 111 shown in FIG. 15 was called a skin type condenser, and had a construction in which iron plates 113 were welded between coolant pipes 112 that were bent back a plurality of times in a bellows shape in the same plane, these being as a whole bent into a spiral shape.
In contrast, condenser 121 shown in FIG. 16 was called a spiral fin type condenser; in this condenser, thin sheet 123 was wound with a prescribed pitch onto the periphery of a cooling pipe 122, which was into bellows shape.
However, in the skin type condenser 111, the flow of air (flow of cooling air current) is fixed in a single direction parallel with iron plates 113 (direction shown by the white arrow in FIG. 15), and a construction in which there is a turbulent flow effect of the cooling air current is difficult to achieve.
Consequently, the heat exchange performance achieved by contact with the cooling air current is poor and in order to obtain the necessary amount of heat exchange, it is necessary to design the iron plates constituting the heat-radiating fins to be of large size; as a result, the total weight of the condenser becomes large and it becomes expensive.
Also, in spiral fin type condenser 121 described above, it was difficult to achieve a compact condenser, since cooling pipe 122 could not be bent in bellows fashion with a small radius of curvature, owing to the obstruction presented by the thin sheet 123 wound on to the periphery of the cooling pipe 122. Also, the operation of winding thin sheet 123 on to coolant pipe 122 was not straightforward, resulting in poor productivity.
The present invention was made in view of the problems of the skin type or spiral fin type condensers used in refrigerators of the type in which the condenser is forcibly air-cooled as described above, its object being to provide a compact condenser for forced cooling of small overall weight, which is inexpensive to manufacture, and which has high heat exchange performance.
In order to achieve the above object, according to the present invention, a forced air-cooling condenser employed in a refrigerator of the type wherein the condenser in which the coolant is condensed is subjected to forced air-cooling using a cooling fan is constructed such that a large number of heat-radiating wires are attached extending across above and below a coolant pipe that is bent back in bellows fashion in the same plane, and this is then as a whole bent into spiral shape or bent into bellows shape.
With a forced air-cooling condenser according to the present invention as described above, since wires are employed as the so-called heat-radiating fins, the overall weight can be reduced compared with a condenser of the skin type, and the coolant pipe can be bent with a smaller radius of curvature than with a condenser of the spiral fin type. Furthermore, since the coolant pipe is bent back in bellows fashion in the same plane and this is then as a whole bent in spiral fashion or bellows fashion, the benefit is obtained that a condenser can be obtained which is compact and yet has high heat exchange performance.
In the present invention: the heat-radiating wires may be attached alternately above and below the coolant pipe; the cross-section of the coolant pipe may be elliptical; the diameter of the heat-radiating wire may be 1.6 mm or less and the pitch of attachment of these heat-radiating wires to the coolant pipe may be 3 to 7 mm; also, the ends of the heat-radiating wires may project on the side of the cooling pipe positioned at both ends; furthermore, there may be provided means for stirring the flow of this cooling air current at a location on the inlet side to the condenser of the cooling air current formed by the cooling fan; and the attachment of the heat-radiating wires to the cooling pipe may be dense in the middle region where the cooling current formed by the cooling fan flows easily and sparse at the edges where the cooling current flows with difficulty; these are all desirable embodiments in that a condenser of high cooling performance by forced air-cooling is thereby produced.